The present invention pertains to wedgelock fastening devices for printed wiring boards. More particularly, it pertains to an improvement upon a current wedgelock fastening device.
Wedgelock fastening devices are utilized for both commercial and military applications for the purpose of retaining printed wiring boards within a chassis. The prior art part is referred to in the Defense Electronics Supply Center from Dayton, OH, Drawing No. 84103, and this part has a code identification number of 14933. The prior art devices comprise a main wedge which is normally adapted such that it may be fastened to a printed wiring board. A first and a second wedge are mounted on a screw assembly. This screw assembly comprises a screw which is passed longitudinally through the first wedge and then through the second wedge. The second wedge having a captive nut mounted upon it such that the screw will pass longitudinally through the wedge and then through the nut. The wedgelock assembly comprises the screw assembly and the main wedge. The screw is located in a channel in the main wedge with the first and second wedge at either end of the main wedge. The main wedge is mounted on a printed wiring board such that when the printed wiring board is inserted into a device, the wedgelock, in a relaxed condition, rides in a slot in the device. When the screw is tightened, the two wedges ride upon the main wedge expanding the wedgelock assembly, whereby the printed wiring board is retained in the device.
The main defect with the current design is in the main wedge assembly. The main wedge has a channel which the screw assembly is inserted through. The channel is hollowed out to allow the screw to pass through the main wedge. At the top of the wedge, the channel narrows to prevent the screw assembly from coming out of the channel. The narrowing of the channel at the top of the main wedge is a design requirement the military and most civilian companies require. A result of this design is the requirement that the screw assembly must be completely disassembled in order to fasten the main wedge to the printed wiring board. Then, upon the main wedge being fastened to the printed wiring board, the screw assembly must be completely reassembled. This operation is tedious and time consuming which adds cost to the manufacturer of the final device. On an individual basis the cost may be insignificant, but for assembly line production the cost of these few steps can become significant. Further, as the wedge assembly must be completely disassembled and then reassembled upon fastening the main wedge to the printed wiring board, it is not possible to place a permanent locking device on the screw to prevent the screw assembly from becoming disassembled.